Correlation of bacterial community with soil physicochemical properties and enzyme activities in rhizosphere soil under different cultivation years of ginseng (Panax ginseng C. A. Mey.)

Objectives Microorganisms and soil enzymes are an important part of the construction of soil microenvironment. Soil quality is closely related to biological indicators such as soil microbial functional diversity and soil enzyme activity. The nutrients, microbial community and enzyme activity of ginseng rhizosphere soil have a great impact on the yield and quality of ginseng. To study the correlation between bacterial community in rhizosphere soil of ginseng and soil physical and chemical indexes and enzyme activity in different cultivation years, so as to provide scientific basis for ginseng cultivation and management.

Methods In ginseng crabapple respectively to collect 3, 4, and 5 years of ginseng rhizosphere soil, village corridor soil as comparison, analysis enzyme activity of soil and its physical and chemical properties, using high-throughput sequencing technologies to determine soil bacterial community composition, diversity, and the rhizosphere bacteria associated with the physical and chemical properties and the enzyme activity analysis, to explore their correlation.

Results The pH, EC, organic matter and nitrate nitrogen of ginseng soil with different cultivation years were significantly different from CK, but there was no difference in total nitrogen, total phosphorus and readily available potassium compared with CK. The four enzyme activities of ginseng soil with different cultivation years were all higher than CK, and the activities of urease and invertase gradually decreased with the increase of cultivation years. High-throughput analysis obtained a total of 2840 OTUs, the unique OTU gradually decreased with the increase of cultivation years. Bacterial community diversity gradually decreased with the increase of cultivation years of ginseng, and the dominant bacteria were Micrococcaceae, Acidobacteriaceae, Nitrosomonadaceae, Gaiellales-uncultured, Xanthomonadaceae, Xanthobacteraceae, Anaerolineaceae. Among them, Anaerolineaceae in CK was 93.41% higher than 5-year-old, and 5-year-old ginseng soil Xanthomonadaceae was 90.99% higher than CK. The analysis of the environmental factors associated with the main bacterial communities in the rhizosphere soil of ginseng for different cultivation years, showed that the microbial community structure of the rhizosphere soil of different cultivation years and the control soil were quite different. Total potassium, acid phosphatase and sucrase were the main environmental factors affecting the three-year-old soil bacterial community, while urease and catalase were the main environmental factors affecting the four-year-old soil bacterial community. Organic matter was negatively correlated with 4, 5 years old soil. There was no strong correlation between the four soil enzymes and 5-year-old soil.

Conclusions The physical and chemical properties, enzyme activities and bacterial community structure of ginseng rhizosphere soil in different cultivation years were significantly different from those of the control. The changes of bacterial community in rhizosphere soil of ginseng in different cultivation years were correlated with soil physical and chemical properties and enzyme activities. The 5-year-old soil enzyme activity decreased, the microbial population using decomposition products decreased, and the microbial community structure changed greatly. The difference of soil bacterial community structure was caused by cultivation years.